Lols.i voted for Allen coz i hope it's his innocence that is the heart innocence...but if you see and hear what the characters have been saying,it isnt necessary that the heart innocence is in ONE exorcist...for all we know,it might be a combination of Krory,Lavi,Leena Lee and Kanda...coz those innocences have been destroyed but they came back! Take leenalee's for example...didnt her innocence protecter by frming a crystal around her body to prevent her from being burnt to ashes by the flames? And Krory...wasnt he supposed to be dead when Jasdero conjured up that spiky-coffin-thingy to kil Krory,but somehow Krory's innocence protected him and gave him the strength and power to continue fighting until he exhausted Jasdero? Those two are rescued from the reach of death by their innocence like Allen was...so i dont kknow...with the story getting so complicated,it could go either way...and as DominationJ stated,Allen might be the heart innocence coz he's the main char...so now we'll have to depend on Katsura Hoshino to give us a suuuper nice ending yaa~!